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What is my DNS server?

SmallPrint asked
My domain has:
2 Domain controllers (windows 2003), which are also internal dns servers. (Internal IP .123 &124)
1 of these DCs is a DHCP server. DHCP hands out 123 & .124 for DNS.

How can I tell what DNS IP  external requests are going to? I know we have our private DNS through our ISP, but need to confirm the exact IP.  Is this configured in the firewall (Cisco ASA)?
Watch Question

Your private DNS should have a forwarder which takes all unknown internal records and points them to an external source. If you are using Windows DNS you can right click on the DNS server in DNS Manager and go to properties. There should be a tab labeled Forwarders.
Top Expert 2011
External requests are forwarded to whatever forwarders you have setup on your DNS servers.
Open up DNS manager, expand until you see the server, right-click on the server ad choose properties, then click on the forwarders tab.
Those are the servers that serve external DNS resolution for you.
Go into your DNS server (either DC)

Check the external forwarder that you are using.  Right click on the zone and hit properties.  Look for the forward section.

That would be your external.

The ASA would only give you DNS if you had the ASA doing DHCP and DNS.


great. I found it.

I have 4 forwarders listed

XX.XX.XX.XX - sbcglobal.net
XX.XX.XX.XX - sbcglobal.net
XX.XX.XX.XX - SMTU   <----What is this?
XX.XX.XX.XX - DNS-RS2 <--- What is this?

Can I just delete SMTU and RS2?
I need to point DNS to an openDNS, so I will be removing the SBC forwarders, but not sure what to do about these unknown.

Alan HardistyCo-Owner
Top Expert 2011

What exactly are you trying to do?
Yes, you can just take them out and replace with the OpenDNS IP's.
I would first test openDNS on another box to make sure it is working the way you like.

Once you do that add openDNS on your DC's but leave your local ISP's...  


are the 2 unknowns most likely some DNS servers that just never go removed?
Most likely, but I wouldn't worry about them.  You can always add them back in if you are having problems =)